Copper alloy



Patented Sept. 20, 1938 UNITED STATES PATENT OFFICE Ind., assignors to P. R. Mallory 8; Indianapolis, Ind., a corporation of Original application'September 15,

No Drawing.

1937, Serial No. 164,038.

(30., Inc., Delaware Divided and this application July 19, 1938, Serial No. 220,006

2 Claims- (CL 75-459) This invention relates to alloys and more par- 331181!!! to copper alloys of improved charactercs. The present application is a division of our 00- 5 pending application, Serial Number 164,038, filed September 15, 1937. r

An object of the invention is to produce an improved copper base alloy.

Another object is to produce a copper-cadmium-cobalt alloy, having a high wear resistance.

Other objects of the invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises a combination of elements, methods of manufacture and the product thereof, brought out and exemplified in the disclosure hereinafter set forth, the scope of the invention being indicated in the appended claims.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the meth- 0d of procedure and the combination of elements iviithout departing from the spirit of the inven- According to the present invention, copper-cobalt-cadmium are improved by the addition of phosphorus, which tends to produce an intermetallic compound with the base forming element present in the alloy; namely, cobalt. By means of the formation of an intermetallic compound, the ternary copper-cobalt-cadmium' alloys can be made of greater hardness, which hardness is also being retained at high tempera- 5 tures.

According to the preferred method of carrying out the present invention, an alloy is made containing copper, cadmium and cobalt, plus phosphorus in the following proportions:

Ca 0.1. to 10% Coba 1 0.1 to 10% Phosphorus ..0.01 to 5% Copper Balance It is possible likewise. to improve the characteristics of other copper-eadmi -cobalt alloys containing small percentages of additional ingredients, by the addition of the above-mentioned compound forming element. mium-cobalt alloys, containing small proportions of silver, zinc, tin, calcium, lithi iron, nickel and manganese, can be improved by the addition of compound forming element phos phorus in substantially the proportions indicated above.

ness in the alloy and marked improvement in the Thus, copper-cad-- The alloy can be made according to standard alloying methods. Thus, an alloy of copper and cobalt may be prepared by melting first the copper and then adding of rondelles or compressed cobalt-copper slugs or anyother form. Afterwards, the cadmium may be added in the form of stick cadmium, or in the form of a cadmium-copper powder mixture or any other suitable form. Finally, the phosphorus may be added and the melt may then be poured into either billets or sand castings. The

the cobalt in the form.

billets can then be further worked down by hot extruding or forging or any similar means. After the alloy has been prepared according to these standard methods, the heat treatment may be carried out as follows:

The alloy is raised in temperature to above 700 degrees C. and preferably to a temperature in the order of 800 to 1,000 degrees C. The alloy is then quenched from this high temperature and subsequently aged at a temperature below 700 degrees C. and preferably in the range between 400 to 600 degrees C. This heat treatment results in a considerable improvement of hardhardness values can be reached exceeding 95 Rockwell 13. Another remarkable effect of the heat treatment is a electrical conductivity, With some alloy combinations within the percentage range given above, a conductivity of of that of pure copper has been obtained.

This alloy is therfore well suited for use at I comparatively high temperatures, since the hardness and electrical conductivity are maintained for indefinite periods at the aging temperatures indicated above. Heat treated alloys, with or without cold working, will retain their properties at a temperature of 450 degrees -C., almost indefinitely.

Alloys which are intended for casting purposes have a preferred cadmium content'of from 0.5 to 5% while in alloys which are intended for further cold or hot working, the maximum cadmium content should be 1.5%. r The material in the cast the aging treatment described above. Instead of giving both treat cuts to the casting, it is also possible to eliminate the quenching treatment, because the material usually gets partly chilled during the casting process and all that is necessary is to apply the second heat treatment, which is generally known as the aging treatment. The materials made in accordance with the present invention were tested for contact resistance after being operated as contactor contacts. It was found that the contact resistance remained very low during long periods of operation, the combined presence of cadmium and cobalt being responsible for the oxide of low resistivity, while the compound forming element produced a mechanical hardness which gave the material a wear resistance superior to that 01' the ternary alloy oi copper, cobalt, and cadmium. The tensile properties of alloys containing cadmium, ranging from 0.25 to 1%; cobalt, from 0.5 to 5%; and phosphorus, ranging from 0.3 to 1%, will reach values of 90,000 to 110,000 p. s. i., with an elongation of 10% or-better, measured in 2 inches. The alloys also have very fine grain structure, which improves the physical properties.

The alloys prepared, as indicated above, are well suited for the manufacture of castings, such I as commutator segments or collector rings for electric machines. In addition, these alloys are suitable for welding electrode tips and welding wheels.

.not desired to be limited thereby, but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed is:

1. An alloy containing about 0.1 to 10% cobalt,

0.1 to 10% cadmium, 0.01 to phosphorus, and the balance copper.

2. An alloy containing 0.25 to 1% cadmium, 0.5 to 5% cobalt, 0.3 to 1% phosphorus and the balance copper, said alloy having high tensile strength and fine grain structure.

FRANZ R. HENSEL. EARL I. LARSEN. 

